Human impact reaches Marianas Trench

The Marianas Trench continues to be a mysterious place for scientists and human beings in general. It remains one of the most inaccessible places on our planet where species of some known and unknown creatures inhabit the area. That’s why it was surprising to know that radioactive material was detected in one of the most remote regions in the Pacific.

The Marianas Trench is a crescent-shaped trough located in the Western Pacific Ocean. It is believed to be roughly 2,550 kilometers long and 69 kilometers wide, with a depth of 36,201 feet below sea level. It is located 200 miles east of the Marianas island chain, in between Japan and Papua New Guinea. Despite its remote location, this has not stopped humanity to have an environmental impact on its unique ecosystem.

A group of scientists, led by earth experts from the Shanghai Ocean University, found traces of the radioactive element Carbon-14, which dates back from the nuclear weapons detonations conducted in the mid-1940s. Traces of the said radioactive element, according to the science and technology website scientificamerican.com, were discovered in some deep-ocean creatures such as shrimp-like crustaceans that inhabit the trench.

The Marians Trench, which is the deepest part of the planet, has not yet been fully explored and a large number of sea creatures have yet to be discovered and cataloged by researchers and other individuals conducting studies on this unique habitat.

Traces of Carbon-14 only showed that anything can get through even in one of the most uninhabited parts of the planet. Carbon-14, measured in levels, is a radioactive isotope produced when neutrons from nuclear reactions collide with nitrogen atoms in the atmosphere. Carbon-14 can also be produced at a lower level from cosmic rays that bombard the earth’s atmosphere. A decade of hydrogen bomb testing in the Pacific during the 1950s has also doubled the atmospheric Carbon-14 levels, where smaller amounts decayed over the years but some managed to spread and taken in as carbon dioxide by plants and eaten by animals and humans alike.

Despite the findings, it remains unclear whether Carbon-14 from those nuclear bomb testing managed to creep its way to the depths of the Mariana Trench. Traces of the radioactive material would have been detected in about the next 1,000 years through natural oceanic circulation. Researchers found out that the water samples taken from the Trench do have traces of Carbon-14, but at a low level than they have been expected as its radiation takes a longer travel time from the surface to the depths of the ocean.

However, higher levels of the element were detected in the tissues and contents of the guts of crustaceans that inhabit the Trench and were caught using the traps left by researchers. Carbon-14 could have reached the deep waters through other means, much faster than the natural way—possibly from the carcasses and other wastes of creatures that can be found above water. It is possible that the radiation from the animals exposed during the nuclear tests was passed on to the crustaceans when they eat their remains.

Radioactive residue from the nuclear weapons testing, and in areas after the Chornobyl and Fukushima disasters were also detected in mountain glaciers that were considered remote areas and seldom visited by humans.

This and the results of research at the Marianas Trench proved that radiation from nuclear bombs can be distributed through oceanic circulation where it even reaches the remote areas on our planet. Glaciers in the arctic region could still have radioactive elements like Americum-241, a product from decayed plutonium. It is possible that radiation from Americum-241 could be released as temperatures continue to rise and the polar ice caps thaw.

Scientists believe humans had drastically changed the atmosphere of the planet, from the seas to the skies and its entire geological landscape. One reason behind this is the nuclear bomb testing done before like on some islands in the Pacific. The evidence found on crustaceans living in the deepest waters of the world is thought to be distant or a remote possibility. But now, humans had also contaminated the farthest depths of the earth.

Microplastics broken down from pieces of large plastic substances along with microbeads and synthetic fibers were also discovered inside the crustaceans that were tested from the Mariana Trench.

The question now is, will human influence continue to reach the deepest part of the ocean, which could further destroy another ecosystem on our very fragile planet? It may take years, but the clock is now slowly ticking.

(This piece was based on research done by scientists from the Shanghai Ocean University and was published on the Scientific American website)